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Marina Drowning Warning
Now for a topic near and dear to me, albeit no joking matter. Since people
started putting shore power on boats there has been an added electrocution,
or shock hazard due to the surrounding water. Much lesser known however, is
the added danger of drowning. For many years, every now and again, someone
would turn up drown in a marina. Most times it was determined to be a person
who drank too much, jumped or fell into the water and drown, no reason to
look any further.
Then back in 1989 or 90 or so in a marina in Ohio a healthy teenage boy
jumped in behind his I/O powered boat and didn’t come up. His buddy jumped
in to get him and he didn’t come up. A 3
rd
boy jumped in to help and all 3
drowned. They were young, healthy, not drinking, and known to be good
strong swimmers. There was no immediate explanation, and an investigation
ensued. Electrical engineers from the ABYC and others were called. I was
working as a marine electrician at the time, a member of the ABYC, and also
teaching the Marine Electronics course for the United States Power Squadron.
I became aware of all this because I was protesting vociferously to the USPS
about their policy of teaching people to cut the green (safety ground) wire at
the shore power inlet to their boats. It was actually a test question, and if you
chose the answer to leave it intact you got it marked wrong! This had been
their policy for years because it was a good way to prevent galvanic and
electrolytic corrosion of the underwater metal parts on boats, particularly in
salt water. That’s a whole ‘nother topic and I may expand on it in a later article.
It turned out that a faulty battery charger was leaking a very small amount of
AC current through to the DC side of the electric system, that in turn, followed
the DC ground out through the outdrive and through the water to the metal
dock pilings and seawall on its way back to the ground rod at the service entry
(shoreside breaker box). When the boys jumped off the back of the boat, they
jumped right into the stray current field. Here’s the confusing part, the boys
were Not electrocuted, or shocked, the autopsies revealed no evidence of
electrocution, they simply drowned.
By Ron Draper